Door frame for metallurgical furnace



Dec. 21, 1965 E. w. BORMAN 3,224,420

DOOR FRAME FOR METALLURGICAL FURNACE Filed Nov. 2'?, 1963 3 Sheets-Sheet 1 Dec. 21, 1965 E. w. BORMAN DOOR FRAME FOR METALLURGICAL FURNACE 5 Sheets-.ShedI 2 Filed Nov. 27, 1965 Dec. 21, 1965 E. W. BoRMAN 3,224,420

DOOR FRAME FOR METALLURGICAL FURNACE Filed Nov. 27, 1963 3 Sheets-Sheet 5 @ELL/@ United States Patent Oilice 3,224,420 Patented Dec. 2l, 1965 3,224,420 DOGR FRAME FOR METALLURGICAL FURNACE Elmer W. Borman, Hammond, Ind., assigner to Inland Steel Company, Chicago, Ill., a corporation of Delaware Filed Nov. 27, 1963, Ser. No. 326,407 Claims. (Cl. 122-497) The present invention relates generally to door frames for metallurgical furnaces, such as steel mill open hearth furnaces, and more particularly to a iluid cooled door frame in which leakage-causing thermal stresses, normally occurring during furnace operation, are minimized.

Metallurgical furnaces, such as open hearth furnaces, generally include a side wall having a plurality of doorways which provide access to the furnace interior when it is desired to charge the furnace or treat the molten bath inside the furnace. These doorways are conventionally rectangular and are covered by doors vertically movable between open and closed positions. A door sill is normally located at the bottom of the doorway, and the two sides and top of the doorway are dened by a door frame conventionally consisting of a single-piece inverted U- shaped member having a pair of side lsections each joined to a top section at a respective opposite end of the top section. The single-piece door frame has a hollow U- shaped interior through which a cooling fluid is circulated.

During operation of the furnace, the temperature therein varies substantially; and even though the conventional door frame is cooled, the temperature thereof also varies substantially; and there is substantial resulting expansion and contraction of the door frame in both vertical and horizontal directions. This continuous expansion and contraction creates thermal stresses concentrated at the junctions of the two door frame side sections with the top section of the U-shaped frame. Continuous expansion and contraction, with the accompanying concentration of stresses at the junctions of the door .frame sections, eventually cause cracks to occur at the junctions. If cooling uid from the interior of the hollow door frame leaks through these cracks into the furnace and contacts the molten bath, a dangerous explosion can occur.

Accordingly, when such leakage occurs, either the furnace must be shut down or the flow of cooling fluid through the entire U-shaped interior of the door frame must -be shut olf. In the former situation, the door normally covering the doorway must be raised or removed, and the entire door frame must then be removed and be repaired or replaced. In situations wherein the furnace opertion is at a stage at which shutdown is not possible, the leaking door frame is allowed -to remain in place, with the entire door frame deprived of circulating cooling fluid, until such time as shutdown is possible; and in such situations the entire door frame is oftentimes burned out by the relatively high operating temperatures of the furnace. When thi-s occurs the door frame cannot be salvaged, and the entire frame must be scrapped.

The above-described drawbacks of conventional door frames are eliminated by a door frame constructed in accordance with the present invention. In the instant door frame the three sections are separate and discrete rather than being joined together, and the three sections are sufficiently spaced apart or provided with mean-s between the sections to accommodate thermal contraction and eX- pansion. This eliminates the concentration of stresses occurring at the junctions of the three joined sections of conventional door frames, and minimizes the main cause of leakage in door frame-s, thereby requiring only a small fraction of the replacements previously necessarywith the old style frames.

Separate means are provided for circulating cooling fluid through each of the separate sections. Therefore,

should a section of the instant door frame spring a leak, or require replacement, only that separate and discrete section which is leaking need be replaced or is .allowed to remain without cooling fluid if furnace operation is continued -for awhile. The other separate sections continue to receive cooling iiuid during the remainder of the furnace operation and need not be replaced. Accordingly, the extent of door frame bum-out and replacement is minimized; and the time required for replacement is cut substantially, as is the shut-down time lfor the furnace. Furthermore, because the side sections are not connected to the top section, the door need not bc raised or removed to enable removal and replacement of a side section. All that is necessary is merely to swing the door (which is -suspended from abo-ve with cables) slightly to one side.

Another feature of door frames constructed in accordance with the present invention is that the top section of the door frame is integral with the furnace skewback member, a structural member normally located above the doorway and extending thereacross and including means, along that side of the member facing the interior of the furnace, for supporting a portion of the furnace roof. The door frame top section is integral with the skewback member in a manner such that cooling uid circulated through the top section of the door frame cools not only the top section but 'also eectively cools the skewback member. As a result, there is substantial minimization of sagging on the part of the cooled skewback member, which sagging would otherwise occur at elevated temperatures because of the heavy load (the furnace roof) supported by the skewback member.

Another advantage arising from the use of door frames consisting of three separate and discrete sections is that variations in roof height may be employed along the length ofthe furnace with a minimum consideration for the problems arising with respect to the design of the door frame. This is because, no matter the height of the roof, the top section of the instant door frame, integral with the skewback member which supports a portion of the roof, will be the same. The only changes that might be necessary would be in the side sections of the door frame, with the vertical dimensions of the latter being the sole design consideration. With the old style conventional door frame, any change in the height of the roof would require a change in the entire door frame.

Other features and advantages are inherent in the structure claimed `and disclosed or will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying diagrammatic drawings wherein:

FIGURE 1 is a perspective view of an embodiment of a door frame constructed in accordance with the present invention;

FIGURE 2 is a perspective View o-f an embodiment of a skewback furnace structural member with the top section `of the door fname integral therewith, and all constructed in accordance with the present invention;

FIGURE 3 is an enlarged vert-ical sectional view taken along line V3 3: in F IGURE 2;

FIGURE 4 is a rear elevational view of the structural member of 'FIGURE 2;

FIGURE 5 Iis -a perspective view of an embodiment of `a side section of a door frame constructed in accordance with the present invention;

FIGURE '6 is la vertical sectional view of the door frame side section of FIGURE 5;

FIGURE 7 is an enlarged sectional view taken along line 7--7 in FIGURE 6; FIGURE 8 is a sectional View taken along line 8 8 in FIGURE 7;

FIGURE 9 is a schematic diagram `of an embodiment 3 v of a cool-ing Ifluid piping system for a door frame in accordance with the present invention; land FIGURE is a fragmentary front View of a portion of the subject invention.

Referring initially to FIGURE 1, there is indicated generally, at 20, an embodiment of a door frame constructed in a-ccordance with lthe present invention, and comprising a pair of side sections 21, 22 and a top section 23 constituting anintegral portion of a furnace structural skewback :member 24 extending horizontally across the top and beyond the sides .of a `furnace doorway 26 defined by door frame side sections 21, 22, door frame top section 23 and -a conventional cast steel door sill 25. Doorway 26 is located in a fu-rnace side wall 27, 'a fragment of which is outlined by dash-dot lines. Also shown in dash-dot lines are conventional furnace bu-ck stays 28. Door frame sections 21, 22 and 23 are separate and discrete, and door sections 21, 22 are each spaced from a respective opposite end 29, 30 (FIGURES 2 and 4) of .top section 23 by a respective spa-ce 31, 32 (FIGURE 10) sufficient to accommodate thermal expansion on the part of the door sections during operation of the furnace. In other words the distance between mutually facing walls of side sections 21, 22 at the elevation of top section 23 is sufficiently greater than the distance between top section ends 29, 30 to accommodate the t-hermal expansion.

All three door frame sections 21, 22 and 23 are hollow and include means for receiving and confining a cooling fluid. The door frame and furnace include means, to be subsequently described in detail, fo-r circulating cooling fluid throu-gh the door frame section-s, individually.

Referring particularly to FIGURES 2, 3 and 4, 'furnace structural member 24 comprises a web portion 35 integral with upper and lower ilanges 36, 37 respectively. Attached to the front or exterior surface 38 of web portion 35 is a web reinforcing plate 40, extending substantially the entire length of member 24. Web portion 35 and plate 40 together constitute web means for structural member 24.

Attached to the front surface 34 of plate 40 is a housing 41 which cooperates with plate 40 to define -a door Vframe top section 23 including means for holding and coniining a cooling fluid. Housing 41 includes (in addition to top section end walls 29 and 30) a front wall 42, a top wall 43, and a bottom wall 44. Structural member 24, as measured between opposite ends 29, 30 (FIG. 4),

is longer than door frame top section 23, as measured between end walls 29, 30 (lFIG. 2). Fluid is introduced into the container mean-s defined by housing 41 and plate 40 through an inlet conduit 45, and is removed from within the container means through an -outlet conduit 46.

Extending from top yflange -36 of member 24, in an eX- terior direction relative to web portion 35, is a ,flange portion 47 having upper and lower edges 103, 104 (FIG- URE 3). Covering these edges is an elongated-member or tube 48 'having a convex curved surface facing an exterior direction to protect the flexible hoses 106 (FIG- URE 4) of a vertically movable furnace door 105 from injury by edges 103, 104. Tube 48 extends 'for a distance greater than the distance separating the hoses 106 on door 105. Hoses 106 circulate cooling fluid through hollow portions (not shown) of door 105. Flange portion 47 has openings 49, 49a fo-r receiving pipes or hoses communicating with conduits 45, 46.

As shown :in FIGURES 3.and 4, web portion 35 has a rear surface 39 facing the interior of the furnace. Integral with rear surface 39, and substantially coextensive with member 24, is t-he upper horizontal flange 57 of an angle bar 53 having a vertical flange 58 integral with the bottom flange 37 of member 24. Angle bar 53, the lower part of web portion 35, and lower flange 37 all cooperate with a pair of end walls 60, 61 to define a container means.

50 yfor holding and confining a cooling -fluid introduced into said container means through an inlet conduit 54 and removed from container means 50 through an outlet conduit 55. Angle bar 53 also supports a skewbrick (dashdot line 56 in FIGURE 3) constituting -a portion lof a furnace roof 108, said skewbrick containing a slot 59 for receiving a horizontally extending bar 52 constituting key means attached to the rear surface 39 of web portion 35. Key means 52 engages and holds skewbrick 56, and prevents collaps-e of the furnace roof in the event co-ntainer means 50 is burned out, a condition which might occur if circulation of cooling fluid through container means 50 is discontinued.

Container means 50 cools the lower portion of member 24. The container means of door frame top section 23 has a rear side defined by plate 40 which also constitutes part of the web means of member 24. Accordingly the top sections container means is in contacting cooling engagement with the web means of member 24 along the entire area of the rear side of the container means. By cooling the web means of member 24 in the manner described above, member 24 has lower temperature and greater strength at elevated furnace temperatures and can support the load of the furnace roof without danger of buckling.

Referring now to FIGURES 5 through 8, there is illustrated a door frame side or 4leg section 22. It should be noted that side sections 21 and 22 are essentially identical except that one is on the left'hand side of the doorway and the other is on the right hand side.) As previously indicated, side section 22 is hollow and includes container means, for receiving and confining a cooling fluid, defined by a front wall 70, a back wall 71, side walls 72, 73 and top and bottom walls 75, 76 respectively. Extending vertically along the outside of front wall 70 is a bar or member 78 constituting a guide for furnace door 105 (FIGURE 4) during vertical movement of the latter.

Back wall 71 has an opening 79 communicating with a container portion indicated generally at 80 and located behind back wall 71. Container portion 80 is defined by a plurality of walls including end walls 81, 82, rear wall 84, upper wall and lower wall 86.

Cooling fluid is introduced into side section 22 through an inlet pipe 87 extending downwardly into the hollow interior of side section 22 and terminating at a nozzle 89 which extends into container portion 80. A downward extension 90 of pipe 87 is maintained in position at the lower portion of side section 22 by an element 91 extending between pipe extension 90 and rear wall 71 of side section 22.

Located at the top of side section 22 is a bracket 92 for removably attaching section 22 to plate 40 at the exterior surface of the web means of structural member 24.

FIGURE 9 shows a piping arrangement for discontinuing the flow of cooling fluid to any one of door frame sections 21, 22, 23 and container means 50 (located at the lower interior portion of member 24) without discontinuing passage of cooling fluid through the others. This would occur in situations where a leak developed in one of the sections or in container means 50, but not in the others.

A fluid supply conduit is connected by shutoff valves 96, 99 to inlet pipes 87, 87 of side sections 21, 22; by shutoff valve 97 to inlet conduit 54 of container means 50; and by shutoff valve 98 to inlet conduit 45 of top section 23. Outlet pipes 88, 88 from side sections 21, 22, outlet conduit 46 of top section 23, and outlet conduit 55 from container means 50 are all connecetd to a fluid return conduit 100.

In the illustrated embodiment door frame sections 21, 22 and 23 are constructed from steel plates joined by welding. Door frame top section 23 is integrally joined to plate 40 by welding; angle bar 53 is integrally joined to member 24 by welding; and door frame side sections 21, 22 are removably connected to plate 40 and member 24 by conventional fastener means such as screws or bolts V (FIGURE 1) extending through openings 111 in bracket portion 92 of the side sections (FIGURE 5).

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

What is claimed is:

1. In a metallurgical furnace having a side wall with a doorway therein:

a furnace structural member extending horizontally across the top of said doorway and having web means and upper and lower flange means;

means, on that one side of said web means disposed toward the furnace interior, cooperating with said lower fiange means to define a first container, integral with said structural member, for receiving and confining a cooling fluid;

means for passing a cooling fiuid through said first container;

said first container including means for supporting a roof portion of said furnace;

means on the other side of said web means, opposite said one side thereof, integral with and cooperating with the web means to define a door frame top section including a second container for receiving and confining a cooling liuid;

means for passing a cooling fluid through said second container;

a pair of door frame side sections each separate and discrete from the other, from the door frame top section, and from the structural member;

means removably connecting each of said door frame side sections to said other side of the web means adjacent a respective opposite end of said door frame top section;

means defining a pair of spaces, each located between a respective door frame side section and a respective portion of said door frame top section adjacent said side section, for accommodating thermal expansion of said door frame sections;

each of said side sections defining a respective side of said doorway and including means for receiving and confining a cooling fluid;

means for passing a cooling fiuid through each of said side sections;

and sill means defining the bottom of said doorway.

2. In a metallurgical furnace as recited in claim 1 and comprising:

means for discontinuing the passage of cooling fluid through any one of said door frame sections and containers without discontinuing passage of cooling fiuid through the others.

3. In a metallurgical furnace -as recited in claim 1 wherein:

said furnace includes vertically movable door means and a pair of space-apart hose means extending upwardly from said door means;

said upper flange means on said structural member has an edge portion located on said other side of the web means;

and said furnace comprises elongated means, having a convex curved surface facing said other direction, for protecting said hose means from injury by said edge portion, and extending along the edge portion for a distance greater than the distance separating said spaced apart hose means on said door.

4. In a metallurgical furnace as recited in claim 3 and comprising:

key means on said one side of said web means for engaging and holding said roof portion supported on said first container.

5. In a metallurgical furnace as recited in claim 1 and comprising:

key means on said one side of said web means for engaging and holding said roof portion supported on said first container.

6. In a metallurgical furnace having a sidewall doorway with a pair of opposite sides, the combination comprising:

a furnace structural member extending horizontally across the top of said doorway and beyond each of said doorway sides;

said structural member including vertically disposed web means;

means integral with and on the furnace interior side of said structural member for supporting a furnace roof portion;

means, including said web means, defining a horizontally disposed door frame top section on the furnace exterior side of said structural member;

said door frame top section being integral with and undetachable from said structural member;

said door frame top section extendingfrom side to Side of the doorway and having a pair of opposite ends;

said structural member having a pair of opposite ends spaced further apart than the spacing between said opposite ends of the door frame top section;

said door frame top section including means defining the top of said doorway and first container means for receiving and confining a lcooling fluid;

said container means having a rear side disposed toward the furnace interior and defined by said web means, whereby the cooling fiuid within said first container means is in intimate, heat-transferring contact with said web means;

said means for supporting va furnace roof Portion including means, on the furnace interior side of the structural member, defining second container means for receiving and confining a cooling fluid;

and means for passing a cooling fluid through each of said first and second container means.

7. In a metallurgical furnace as recited in claim 6 wherein:

said web means is of reinforced construction relative to the rest of said first container means.

8. In a metallurgical furnace having a sidewall 'doorway with a pair of opposite sides, the combination comprising:

a furnace structural member extending horizontally across the top of said doorway and beyond each of said doorway sides;

said structural member including vertically disposed web means;

means integral with and on the furnace interior side of said structural member for supporting a furnace roof portion;

means, including said web means, defining a horizontally disposed door frame top section on the furnace exterior side of said structural member;

said `door frame top section being integral with and undetachable from said structural member;

said door frame top section extending from side to side of the doorway and having a pair of opposite ends;

said structural member having a pair of opposite ends spaced further apart than the spacing between said opposite ends of the door frame top section;

said door frame top section including means defining the top of said doorway and container means for receiving and confining a cooling fluid;

means for passing a cooling fluid through said container means;

said container means having a rear side disposed toward the furnace interior and defined by said web means, whereby the cooling fluid within said container means is in intimate, heat-transferring contact with said web means;

a pair of spaced-apart door frame side sections, each "7 including means defining a respective opposite side of said doorway, and eachbeing separate and discrete from the other side section and from the door frame top section;

each of said side sections including means for receiving and confining a cooling fiuid;

means for passing a cooling uid through each of the side sections;

means defining a Vpair of spaces, each located between a respective door frame side section .and a respective portion of the door frame top section adjacent said sidey section, for accommodating thermal expansion of the three door frame sections;

means removably connecting each of said side sections to said furnace structural member;

and means defining the bottom of 4said doorway.

9. In a metallurgical furnace having a sidewall doorway with a pair of opposite sides, the combination comprising:

a furnace structural member extending `horizontally across the top of said doorway and beyond each f said doorway sides;

means on the furnace interior side of said structural member for supporting a furnace roof portion;

means, on the furnace exterior side of said structural i member, defining a Ahorizontally disposed door frame top section;

said door frame top section including means defining the top of said doorway and container means for receiving and confining a cooling fluid;

means for passing a cooling fluid through said container means;

a pair of spaced-apart door frame side sections, each including means defining a respective opposite side of said doorway, and each being separate and discrete fromthe other side section Iand from the door frame top section;

each of said side sections including means for receiving and confining a cooling uid;

means for passing a cooling fluidthrough each of the side sections;

means defining a pairof spaces, each located between a .respective door frame side section and a respective portion of the door frame top section adjacent 40 said side section, for accommodating thermal expansion of the three door frame sections;

and means removably connecting each of said side sections to the furnace exterior side of said furnace structural member.

10. In a metallurgical furnace having a sidewall doorlway with ,a rpair of opposite sides, the combination comprising:

a furnace structural member extending horizontally across the top of saiddoorway land beyond each of said doorway sides;

means, on the furnace exterior side of said structural member, `defining a'horizontally disposed door frame top section;

said door frame ,top section including means defining the top of saididoorway and container means for receiving and confining a cooling uid;

means for ypassing -a cooling :fluid through said container means;

a pair of'spaCed-apart door frame side sections, each including means defining a respective opposite side of said doorway, and each being separate and discrete from the other side section and from the door frame top section;

each of said side sections including means for receiving and confining acooling fluid;

means for passing a cooling fluid through each of the side sections;

means defininga pair of spaces, each located between a respective door frame side section and a `respective portion of the door frame top section adjacent said side section, for accommodating thermal expansion of the three door frame sections;

and means removably connecting each of said side sections to said .furnace structural member.

References Cited by the Examiner UNITED STATES PATENTS 1,168,649 1/1916 Knox 122-497 1,529,193 3/1925 Lewis 110-172 2,427,547 9/ 1947 Bulmer 122-499 2,688,956 9/1954 Pottmeyer 122-497 2,840,046 6/ 19518 Pottmeyer 122-6 FOREIGN PATENTS 774,209 l5/ 1957 Great Britain.

FREDERICK MATTESON, IR., Primary Examiner.

KENNETH W. SPRAGUE, Examiner.

UNITED STATES yPATENT OFFICE CERTIFICATE 0F CGRRECTION Patent No. 3,224,420 December 21, 1965 Elmer W. Borman It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the drawings, Sheet 1, Fig. 4, strike out the numerals "29" and "30"; column 1, 1ine 49, for "opertion" read operation column 3, 1ine 19, for "(FIGURES 2 and 4)" read (FIGURE 2) line 43, after "f1uid." insert The web means of structural member 24 is of reinforced construction relative to housing 41. line 46, strike out "29, 30"; column 4, line 24, for "It" read (It column 5, line 56, for "space-apart" read spaced-apart Signed and sealed this 3rd day of January 1967.

(SEAL) Amst:

ERNEST W. SWIDER EDWARD I. BRENNER Attesting Offir Commissioner of Patents 

1. IN A METALLURGICAL FURNACE HAVING A SIDE WALL WITH A DOORWAY THEREIN: A FURNACE STRUCTURAL MEMBER EXTENDING HORIZONTALLY ACROSS THE TOP OF SAID DOORWAY AND HAVING WEB MEANS AND UPPER AND LOWER FLANGE MEANS; MEANS, ON THAT ONE SIDE OF SAID WEB MEANS DISPOSED TOWARD THE FURNACE INTERIOR, COOPERATING WITH SAID LOWER FLANGE MEANS TO DEFINE A FIRST CONTAINER, INTEGRAL WITH SAID STRUCTURAL MEMBER, FOR RECEIVING AND CONFINING A COOLING FLUID; MEANS FOR PASSING A COOLING FLUID THROUGH SAID FIRST CONTAINER; SAID FIRST CONTAINER INCLUDING MEANS FOR SUPPORTING A ROOF PORTION OF SAID FURNACE; MEANS ON THE OTHER SIDE OF SAID WEB MEANS, OPPOSITE SAID ONE SIDE THEREOF, INTEGRAL WITH AND COOPERATING WITH THE WEB MEANS TO DEFINE A DOOR FRAME TOP SECTION INCLUDING A SECOND CONTAINER FOR RECEIVING AND CONFINING A COOLING FLUID; 